1. Field of the Invention
The present invention relates to production equipment and fixtures; specifically, it relates to a mold assembly to manufacture an object with a hole, and a device for extracting a mold core from the mold assembly.
2. Descriptions of the Related Art
While manufacturing one-piece plastic parts using current technology, such as the blade parts with multiple inward holes (as the part 110 shown in FIG. 1) of a fan frame, a plurality of mold cores used for extraction have to be disposed in the mold assembly to completely strip the mold of inward concaves and form holes or wind tunnels in the blade accordingly. In view of current mold core extraction structures, an appended mold core extraction hydraulic pump corresponding to each of the holes is disposed in the mold assembly. As shown in FIG. 4, a plurality of mold core extraction hydraulic pumps 101, 102, 103, 104, 105, 106, 107, 108, and 109 are disposed correspondingly to each mold core extraction shaft on the mold base. After raw materials for plastic products have been injected into the mold, the mold core can be extracted out of the mold using the hydraulic pump to form the product with holes or tunnels therein, such as the product with nine wind tunnels shown in FIG. 1.
However, the aforementioned production and manufacturing methods have drawbacks, such as complicated mold assembly structures, large profiles, imprecise assembly for mold core extraction, and heavy weights needed for the injection molding machines. As a result, these drawbacks are not economically efficient.
In view of these drawbacks, the aforementioned mold assembly and mold device for extracting the mold core have to be redesigned to satisfy the following requirements: small volume, space-saver, easy maintenance and high precision.